Boiler Emission Standards for Coal
Boiler Emission Standards for Coal
Coal boilers are one of the major targets of environmental protection governance in China today, and this is because they are the culprit behind disasters such as smog, directly harming people’s health and quality of life. Coal boilers (mainly 10t or less small coal-fired boilers) are now being strictly controlled by various provinces and cities, mainly because the flue gas they emit is a highly polluting gas that pollutes the environment and further harms public health. The control of coal boiler flue gas emissions is mainly carried out in two aspects:
1. Control of sulfur dioxide emissions
It is well known that sulfur dioxide pollution caused by sulfur dioxide is very large, so the country’s governance of new chain grate stoker coal-fired boilers and even circulating fluidized bed coal-fired boilers is very strict today, so that boiler manufacturers need to use efficient, energy-saving and environmentally friendly technologies to achieve desulfurization efficiency of 75-85% and emission standards of 300 mg/m3. Of course, only truly good boiler manufacturers have the ability to achieve this. In addition, for coal with a sulfur content of 2.0% or more, strengthening washing can remove 30-60% of the sulfur content, especially in China’s high sulfur coal-producing regions, it is necessary to strengthen the raw coal washing rate, establish regional blending centers, and coordinate the combustion desulfurization work to truly ensure that the standard is met.
2. Control of carbon monoxide emissions
The average emission concentration of NOx from Chinese small and medium-sized layer-fired boilers is 24.6 mg/m3, of which about 30% of the number of boilers with emissions less than or equal to 300 mg/m3 accounts for about 10% of the number of boilers with emissions less than 100mg/m3. Formed coal has the lowest emission concentration of around 100mg/m3 due to its lower combustion temperature, and the emission concentration of coal powder boilers is in the range of 500-800mg/m3, while that of chain grate boilers is in the range of 340-530mg/m3, and that of circulating fluidized bed boilers is lower, in the range of 150-300mg/m3. For new coal-fired boilers of various boiler types, using low-nitrogen combustion technology to achieve 300mg/m3 is a normal emission level; in addition, for 200mg/m3, improvements are needed in furnace design and air supply mode.